Reference?

Re: Reference?

Kris Caselden wrote:
[color=blue]
> I've searched all the Python docs I could find, but I haven't seen any
> mention of referencing function arguments, such as you would with the
> & in c/c++. Is this possible in Python?[/color]

The analog of the Python way of handling args among the C-style languages is
Java. So, no, you are on mission impossible :-)

class Mutable:
pass

v1 = Mutable()
v1.name = "v1"
v2 = "v2" #strings are immutable

def fun(a1, a2):
a1.name = "a1"
a2 = "a2"
fun(v1, v2)

print v1.name # prints a1
print v2 # prints v2

As a workaround, you can do:

def fun2():
a1 = Mutable()
a1.name = "A1"
return a1, "A2"

v1, v2 = fun2()

print v1.name # prints A1
print v2 # prints A2

See the tutorial (http://www.python.org/doc/current/tut/node6.html) for the
tricks you *can* do with function arguments

Peter

Re: Reference?

Kris Caselden wrote:
[color=blue]
> I've searched all the Python docs I could find, but I haven't seen any
> mention of referencing function arguments, such as you would with the
> & in c/c++. Is this possible in Python?[/color]

The analog of the Python way of handling args among the C-style languages is
Java. So, no, you are on mission impossible :-)

class Mutable:
pass

v1 = Mutable()
v1.name = "v1"
v2 = "v2" #strings are immutable

def fun(a1, a2):
a1.name = "a1"
a2 = "a2"
fun(v1, v2)

print v1.name # prints a1
print v2 # prints v2

As a workaround, you can do:

def fun2():
a1 = Mutable()
a1.name = "A1"
return a1, "A2"

v1, v2 = fun2()

print v1.name # prints A1
print v2 # prints A2

See the tutorial (http://www.python.org/doc/current/tut/node6.html) for the
tricks you *can* do with function arguments

Peter

Re: Reference?


"Kris Caselden" <google@hanger. snowbird.net> schrieb im Newsbeitrag
news:abc3fdd3.0 308230057.6b309 [email protected] gle.com...
[color=blue]
> I've searched all the Python docs I could find, but I haven't seen any
> mention of referencing function arguments, such as you would with the
> & in c/c++. Is this possible in Python?[/color]

Your question is probably not as sophisticated: Parameter passing in Python
is *always* like & in C++.

There had been an exaustive disyussion some weeks ago: here is my
contribution:

Sent: Wednesday, August 13, 2003 9:12 AM
Subject: Re: two quick questions

[color=blue]
> The following examples might clear the more theoretical elaborations .....
>
>
> def noUse(a):
> a=(4,5,6)
>
> def tricky(a):
> a[0]=(7,8,9)
>
> # case 1
> x=[1,2,3]
> print x
> tricky(x)
>
> x=(1,2,3)
> # case 2
> noUse(x)
> print x
>
> # case 3
> tricky([x])
> print x
>
> # case 4
> y=[x]
> tricky (y)
> print x
> print y[0]
>
> # case 5
> tricky(x)
> print x
>
>
> Kindly
> Michael Peuser[/color]

Re: Reference?


"Kris Caselden" <google@hanger. snowbird.net> schrieb im Newsbeitrag
news:abc3fdd3.0 308230057.6b309 [email protected] gle.com...
[color=blue]
> I've searched all the Python docs I could find, but I haven't seen any
> mention of referencing function arguments, such as you would with the
> & in c/c++. Is this possible in Python?[/color]

Your question is probably not as sophisticated: Parameter passing in Python
is *always* like & in C++.

There had been an exaustive disyussion some weeks ago: here is my
contribution:

Sent: Wednesday, August 13, 2003 9:12 AM
Subject: Re: two quick questions

[color=blue]
> The following examples might clear the more theoretical elaborations .....
>
>
> def noUse(a):
> a=(4,5,6)
>
> def tricky(a):
> a[0]=(7,8,9)
>
> # case 1
> x=[1,2,3]
> print x
> tricky(x)
>
> x=(1,2,3)
> # case 2
> noUse(x)
> print x
>
> # case 3
> tricky([x])
> print x
>
> # case 4
> y=[x]
> tricky (y)
> print x
> print y[0]
>
> # case 5
> tricky(x)
> print x
>
>
> Kindly
> Michael Peuser[/color]

Re: Reference?

On Sat, Aug 23, 2003 at 01:57:33AM -0700, Kris Caselden wrote:[color=blue]
> I've searched all the Python docs I could find, but I haven't seen any
> mention of referencing function arguments, such as you would with the
> & in c/c++. Is this possible in Python?[/color]

Python is pass-by-reference by default.
[color=blue][color=green][color=darkred]
>>> f = []
>>> def foo(n):[/color][/color][/color]
.... n.append("hi")
....[color=blue][color=green][color=darkred]
>>> foo(f)
>>> print f[/color][/color][/color]
['hi']

--
m a c k s t a n n mack @ incise.org http://incise.org
A bore is someone who persists in holding his own views after we have
enlightened him with ours.